Molding compositions containing thermoplastic polyurethane (herein "TPU") and graft polymers of olefinically unsaturated monomers are known. Compositions of this type and having good mechanical properties, most notably tear resistance, were disclosed in U.S. Pat. No. 3,049,505. Also noted is U.S. Pat. No. 4,317,890 which disclosed relevant compositions which contain a predominant amount of TPU. In this patent there is no distinction made between polyether-polyol based TPU's and their polyester-polyol based counterparts. Compositions containing polyether-polyol derived TPU, ABS and an acrylic polymer processing aid additive have been disclosed in U.S. Pat. No. 4,179,479. Nothing is disclosed in this document relative to gloss values or to thermoformed articles prepared from the compositions. Injection molded compositions said to exhibit improved strength, expansion coefficient, wear, gasoline and hydrolysis resistance were disclosed in German DOS 3,931,419. Nothing relative to thermoforming or the attainment of low gloss has thus been disclosed. U.S. Pat. Nos. 4,317,890 and 4,342,847 both disclosed compositions containing TPU and ABS, yet neither evidenced a recognition in this context of the critical difference between polyether polyol-based TPU and its polyester polyol based counterparts.
Also relevant is U.S. Pat. No. 5,491,194 which disclosed a composition containing a thermally processable, high modulus polyurethane and mass-polymerized ABS, the composition said to exhibit improved solvent resistance and greater impact strength and stiffness than the comparable composition which is based on emulsion-ABS. The polyurethane component of the disclosed composition is characterized in that its tensile modulus is at least 150,000 psi. Further relevant is U.S. Pat. No. 5,055,525 which disclosed a composition containing relevant rubber, including ABS, and a polyester polyol-based TPU. The composition is said to exhibit low temperature impact strength. In fact, the disclosure, in column 6 line 34, et seq., teaches away from using polyether polyol-based TPU (wherein 50 percent or more of the of the soft segment content is composed of ether-linked repeating units) in the context of that invention.
The present invention is directed to a thermoplastic composition especially suitable for the preparation of thermoformed articles having low gloss and "soft-touch". These articles have in recent years found applicability in the preparation of interior automotive parts.